Forms Pro - survey language is translating when not required.

When using Forms Pro I am experiencing language translations despite not selecting Multilingual in the settings section. 

As an example, I have sent an English language survey to someone in Germany. In the settings section of the form the language is set to English, but when the 'Thank you' page shows, 'Thank you' is translated in to German. The same translation process, from English in to German also happens for the instruction to select from a drop down field (Ihre Antwort auswählen). 

I do not want any additional translation at all for the survey. Does anyone know how this can be achieved?